<b><i>Introduction:</i></b> There is an inconclusive causal association between asthma symptoms and dental caries in the primary dentition. This study aimed to investigate, using SEM (structural equation modeling), a possible causal relation between asthma and dental caries in the primary dentition. <b><i>Methods:</i></b> Using data from the 2004 Pelotas Birth Cohort Study, a sub-sample of 1,303 individuals was selected. Dental caries was clinically evaluated at 5 years old based on decayed, missing, and filled tooth (dmft) index criteria. Asthma-related symptoms (wheezing and shortness of breath) at 1- and 4-year-olds composed a latent variable and were the main exposures to caries occurrence. SEM was used to identify possible direct, indirect, and mediated effects of asthma in primary dentition dental caries. <b><i>Results:</i></b> The general prevalence of caries at age 5 was 1.95 (SD: 3.56). When comparing the dmft values for children with asthma symptoms and those without, they presented similar values in both periods where asthma symptoms were evaluated (1- and 4-year-old). SEM analysis showed that asthma was neither directly nor indirectly related to dental caries. <b><i>Conclusion:</i></b> Asthma, using a latent variable constructed based on asthma symptoms, showed no causal effect on dental caries occurrence in the primary dentition.